1. Field of the Invention
The present invention relates to a micro manipulator for moving an electrode, a driving method thereof, and a measuring device of a brain signal using the same, and more particularly to a micro manipulator capable of moving an electrode to a desired position through the more precise movement of the electrode approaching the cranial nerve cells, a driving method thereof, and a measuring device of a brain signal using the same.
2. Description of the Prior Art
Typically, there are approximately 1011 neurons in a brain of a human being, and the neurons transfer information by means of electric signals. For the analysis of a function of the neuron, there have been proposed analysis methods for analyzing an electrical characteristic of the brain neuron for an external stimulus, and a vital reaction under an electrical stimulus for specified brain neuron.
A conventional measuring device for measuring a brain signal of the brain neurons is shown in FIG. 1. The conventional brain signal measuring device includes an electrode 32 for detecting an electric signal of the brain neurons or applying an electric signal to the brain neurons, a micro-manipulator 30 for moving the electrode 32 nearer to or away from the brain neurons, and a signal processor 50 for amplifying an electric signal from the electrode 32, converting the amplified signal into a digital signal, and analyzing the digital signal.
FIG. 2 is a schematic view illustrating a construction of a conventional micro manipulator 30. In FIG. 2, the conventional micro manipulator 30 includes a lower support 34 fixed to the upper portion of a skull 48, a drive shaft 39 and a guide bar installed perpendicular to the lower support 34, an upper support 36 moving vertically along the guide bar 38 by the drive shaft 39, an electrode holder 40 fixedly installed to the upper support 36 to pass through the lower support 334, and an electrode 32 fixedly inserted into the electrode holder 40.
The drive shaft 39 is rotatably installed on the lower support 34 and whose outer surface is threaded. In addition, the upper support 36 has therein a drive hole 37 through which the drive shaft 39 passes and whose inner wall is threaded, so that the upper support 36 moves upward or downward (vertically in FIG. 2) along the guide bar 38 according to a rotation direction of the drive shaft 39.
Together with the upward or downward movement of the upper support 36, the electrode 32 held in the electrode holder 40 installed on the upper support 36 also moves upward or downward. Accordingly, an operator rotates the drive shaft 39 to move the electrode 32 nearer to or away from the brain neurons (not shown) in the skull 48. In this case, a capability to move the electrode 32 to a desired position from the brain neurons is called a distance resolution.
In the conventional manipulator 30, the movement of the upper support 36 and the electrode 32 is regulated by the adjustment of a pitch of screw reads and a rotation angle of the drive shaft 39. Thus, in the conventional micro manipulator, with all precise manufacturing of the drive shaft, there is a limit to accurately regulate the electrode, so that the distance resolution is considerably reduced, causing a problem in that it is difficult to accurately position the electrode to a desired position from the brain neurons.